Oedema is an abnormal accumulation of fluid in the tissue spaces or cavities of the body. There are five main factors in the formation of generalised oedema and a sixth which plays an important role in the formation of local oedema.
There are:
1.Permability of the capillary wall, PA1 2. & 3.Colliodal osmotic presure of the plasma proteins in the blood and tissues. PA1 4. & 5.Hydro-static pressures in the capillaries and tissues, and
6.Lymphatic obstruction
Thus oedema is an unusual swelling of the tissue due to an excessive amount of fluid and can be the result of various causes. Thus haematoma, or in other words a bruise, is one of the most common oedemas. The causes of oedema fall naturally into four groups corresponding to the four classes of oedema, thus
1.High-flow low-protein
2.High-flow high-protein,
3.Low flow high protein, as well as a fourth group of causes of oedema "safety valve insufficiency" which occurs when lymphostasis is superimposed on what would normally be a high flow oedema produced either by excess blood vascular leakage, or the obstruction of a duct of an organ (kidney, pancreas, etc.) the results of which are particularly disastrous for the tissues.
High-protein oedemas are very common in all communities. It has been found that one person in three seeks medical attention every year, in south Australia, for a condition associated with one. The W.H.O. estimates that 250,000,000 people suffer from lymphoedema and elephantiasis, while 250,000 women in Australia suffer from lymphoedema of the arm, of varying grades of severity, after mastectomy. It is highly probable that the improvement produced by the benzo-pyrone group of drugs, in so many different diseases is because they have high-protein oedema associated with them. This always causes reduced oxygenation and function of the tissues. If the oedema is reduced, oxygenation and function are improved. While these drugs do not affect the basic diseases the reduction they produce in associated oedemas improve the function of the tissues and thus the normal healing processes proceed more expeditiously. Examples of this are: lymphoedema, accidental and surgical trauma, haematomas, pancreatitis, heptitis and cirrhosis.